Trucks, and particularly tanker trucks, are widely used for transporting a multitude of different liquids. One very specific use of tanker trucks is to deliver water to fires in rural areas where water supply from hydrants is not available. Fire tanker trucks used for carrying water commonly do so by taking on a load from an auxillary source, as described below, rushing to the scene of the fire, rapidly unloading the water supply into a temporary structure, and returning thereafter for additional water. In fire service, this is referred to as a "water shuttle". It may involve one or more auxilliary water source, including pumpers, pumper/tankers, pond pumpers, or pressure hydrants. Such sources load tankers of many different types, which tankers transport the water to the fire scene.
A vacuum fire tanker is equipped to load itself rapidly and efficiently without the use of an auxilliary source. But it is often advantageous, and occasionally even mandatory, that a vacuum fire tanker be used in a water shuttle involving an auxilliary source. When this is the case, the vacuum fire tanker's closed tank system must have a safe, controlled venting capability. It is an object of this invention to provide both safety and control.
Because of the rural locale, the truck is operated at high speeds, frequently on uneven terrain and, not uncommonly, with frequent, sudden braking. Since the ability to fight the fire is often directly related to the number of gallons of water per minute that can be delivered to the fire scene, the efficiency of rural fire fighting can be increased by increasing either the capacity of the truck to hold water, the ability of the truck to operate safely at higher velocities, or both. It is the object of this invention to increase both factors.
One solution for this problem has been proposed in my U.S. Pat. No. 4,789,170. In that patent, I disclose a system for inserting baffles in such tanker trucks to subdivide the inertial forces generated by the load shift in a liquid load, thereby attenuating such forces. The present invention may be used either with or without such baffles.